GB1215689A - Method for dosing chlorine or fluorine into halogen-cycle-type incandescent lamps - Google Patents

Abstract

1,215,689. Electric incandescent lamps. WESTINGHOUSE ELECTRIC CORP. 6 Oct., 1969 [5 Nov., 1968], No. 48984/69. Heading H1F. Chlorine and/or fluorine are introduced into the envelope of an incandescent lamp in the form of the corresponding carbonyl halide. In one embodiment the lamp is filled to a pressure of 1 to 3 atmospheres with a mixture consisting of 90% argon and 10% nitrogen together with equimolar proportions of carbonyl fluoride (COF 2 ) and carbonyl chloride (COCl 2 ) in an amount constituting from 0À01 to 0À30 (preferably from 0À02 to 0À05) volume per cent of the total gaseous filling. Alternatively, equimolar proportions of carbonyl fluoride and elemental iodine and/or bromine may be employed. In another embodiment iodine and/or bromine are added in the form of heat-decomposable compounds such as methylene iodide or methylene bromide, and in a further embodiment 0À05 volume per cent of carbon monoxide is also included. The envelope may be cooled in liquid nitrogen during the filling operation if the final pressure of the filling is to be above atmospheric, the carbonyl halide and inert gas being introduedd through an exhaust tubulation which is subsequently tipped off at a distance from the envelope. Iodine or bromine, when required, are placed in a side branch of the tubulation in elemental or compound form and are then introduced into the envelope by heating the branch, after which the envelope is partly removed from the liquid nitrogen bath to enable the tubulation to be tipped off close to the envelope.